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Date: Tue, 30 Aug 2011 00:05:33 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: riyer@...dia.com
Cc: rydberg@...omail.se, axel.lin@...il.com, olof@...om.net,
amartin@...dia.com, linux-kernel@...r.kernel.org,
linux-input@...r.kernel.org
Subject: Re: [PATCH v1] Input: tegra-kbc - fix wakeup from suspend.
Hi Rakesh,
On Thu, Aug 25, 2011 at 05:29:47PM -0700, riyer@...dia.com wrote:
> From: Rakesh Iyer <riyer@...dia.com>
>
> For wakeup to be reliable, kbc needs to be in interrupt mode before suspend.
> Created common routine to control the FIFO interrupt.
> Added synchronization to ensure orderly suspend.
>
> Signed-off-by: Rakesh Iyer <riyer@...dia.com>
> ---
> drivers/input/keyboard/tegra-kbc.c | 83 +++++++++++++++++++++++++++++-------
> 1 files changed, 67 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
> index a5a7791..41de11f 100644
> --- a/drivers/input/keyboard/tegra-kbc.c
> +++ b/drivers/input/keyboard/tegra-kbc.c
> @@ -38,7 +38,7 @@
> #define KBC_ROW_SCAN_DLY 5
>
> /* KBC uses a 32KHz clock so a cycle = 1/32Khz */
> -#define KBC_CYCLE_MS 32
> +#define KBC_CYCLES_PER_MS 32
This seems to be an unrelated change, can it be split out?
>
> /* KBC Registers */
>
> @@ -55,6 +55,7 @@
>
> #define KBC_ROW_CFG0_0 0x8
> #define KBC_COL_CFG0_0 0x18
> +#define KBC_TO_CNT_0 0x24
> #define KBC_INIT_DLY_0 0x28
> #define KBC_RPT_DLY_0 0x2c
> #define KBC_KP_ENT0_0 0x30
> @@ -70,8 +71,10 @@ struct tegra_kbc {
> spinlock_t lock;
> unsigned int repoll_dly;
> unsigned long cp_dly_jiffies;
> + unsigned int cp_to_wkup_dly;
> bool use_fn_map;
> bool use_ghost_filter;
> + bool in_suspend;
> const struct tegra_kbc_platform_data *pdata;
> unsigned short keycode[KBC_MAX_KEY * 2];
> unsigned short current_keys[KBC_MAX_KPENT];
> @@ -341,6 +344,18 @@ static void tegra_kbc_report_keys(struct tegra_kbc *kbc)
> kbc->num_pressed_keys = num_down;
> }
>
> +static void tegra_kbc_set_fifo_interrupt(struct tegra_kbc *kbc, bool enable)
> +{
> + u32 val;
> +
> + val = readl(kbc->mmio + KBC_CONTROL_0);
> + if (enable)
> + val |= KBC_CONTROL_FIFO_CNT_INT_EN;
> + else
> + val &= ~KBC_CONTROL_FIFO_CNT_INT_EN;
> + writel(val, kbc->mmio + KBC_CONTROL_0);
> +}
> +
> static void tegra_kbc_keypress_timer(unsigned long data)
> {
> struct tegra_kbc *kbc = (struct tegra_kbc *)data;
> @@ -348,6 +363,14 @@ static void tegra_kbc_keypress_timer(unsigned long data)
> u32 val;
> unsigned int i;
>
> + /* Exit immediately if driver is trying to enter suspend. */
> + spin_lock_irqsave(&kbc->lock, flags);
> + if (kbc->in_suspend) {
> + tegra_kbc_set_fifo_interrupt(kbc, true);
> + spin_unlock_irqrestore(&kbc->lock, flags);
> + return;
> + }
> + spin_unlock_irqrestore(&kbc->lock, flags);
> val = (readl(kbc->mmio + KBC_INT_0) >> 4) & 0xf;
> if (val) {
> unsigned long dly;
> @@ -370,9 +393,7 @@ static void tegra_kbc_keypress_timer(unsigned long data)
>
> /* All keys are released so enable the keypress interrupt */
> spin_lock_irqsave(&kbc->lock, flags);
> - val = readl(kbc->mmio + KBC_CONTROL_0);
> - val |= KBC_CONTROL_FIFO_CNT_INT_EN;
> - writel(val, kbc->mmio + KBC_CONTROL_0);
> + tegra_kbc_set_fifo_interrupt(kbc, true);
> spin_unlock_irqrestore(&kbc->lock, flags);
> }
> }
> @@ -380,15 +401,14 @@ static void tegra_kbc_keypress_timer(unsigned long data)
> static irqreturn_t tegra_kbc_isr(int irq, void *args)
> {
> struct tegra_kbc *kbc = args;
> - u32 val, ctl;
> + unsigned long flags;
> + u32 val;
>
> /*
> * Until all keys are released, defer further processing to
> * the polling loop in tegra_kbc_keypress_timer
> */
> - ctl = readl(kbc->mmio + KBC_CONTROL_0);
> - ctl &= ~KBC_CONTROL_FIFO_CNT_INT_EN;
> - writel(ctl, kbc->mmio + KBC_CONTROL_0);
> + tegra_kbc_set_fifo_interrupt(kbc, false);
>
> /*
> * Quickly bail out & reenable interrupts if the fifo threshold
> @@ -397,16 +417,18 @@ static irqreturn_t tegra_kbc_isr(int irq, void *args)
> val = readl(kbc->mmio + KBC_INT_0);
> writel(val, kbc->mmio + KBC_INT_0);
>
> - if (val & KBC_INT_FIFO_CNT_INT_STATUS) {
> + /* Exit immediately if driver is trying to enter suspend. */
> + spin_lock_irqsave(&kbc->lock, flags);
> + if (!kbc->in_suspend && (val & KBC_INT_FIFO_CNT_INT_STATUS))
> /*
> * Schedule timer to run when hardware is in continuous
> * polling mode.
> */
> mod_timer(&kbc->timer, jiffies + kbc->cp_dly_jiffies);
> - } else {
> - ctl |= KBC_CONTROL_FIFO_CNT_INT_EN;
> - writel(ctl, kbc->mmio + KBC_CONTROL_0);
> - }
> + else
> + tegra_kbc_set_fifo_interrupt(kbc, true);
> +
> + spin_unlock_irqrestore(&kbc->lock, flags);
>
> return IRQ_HANDLED;
> }
> @@ -648,7 +670,7 @@ static int __devinit tegra_kbc_probe(struct platform_device *pdev)
> debounce_cnt = min(pdata->debounce_cnt, KBC_MAX_DEBOUNCE_CNT);
> scan_time_rows = (KBC_ROW_SCAN_TIME + debounce_cnt) * num_rows;
> kbc->repoll_dly = KBC_ROW_SCAN_DLY + scan_time_rows + pdata->repeat_cnt;
> - kbc->repoll_dly = DIV_ROUND_UP(kbc->repoll_dly, KBC_CYCLE_MS);
> + kbc->repoll_dly = DIV_ROUND_UP(kbc->repoll_dly, KBC_CYCLES_PER_MS);
>
> input_dev->name = pdev->name;
> input_dev->id.bustype = BUS_HOST;
> @@ -735,10 +757,29 @@ static int tegra_kbc_suspend(struct device *dev)
> struct tegra_kbc *kbc = platform_get_drvdata(pdev);
>
> if (device_may_wakeup(&pdev->dev)) {
> - tegra_kbc_setup_wakekeys(kbc, true);
> - enable_irq_wake(kbc->irq);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&kbc->lock, flags);
> + kbc->in_suspend = 1;
> + spin_unlock_irqrestore(&kbc->lock, flags);
> +
> + del_timer(&kbc->timer);
I'd expect this to be del_timer_sync().
Overall I think this is quite complex, do we really need to keep
interrupts enabled (as in enable_irq) for wakeup to work? It is my
understanding that wakeup (enable_irq_wake/disable_irq_wake) control is
separate from enable_irq/disable_irq control. If you can do
disable_irq() while system goes to sleep then the code will be much
simpler.
Thanks.
--
Dmitry
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